Geode GXLV Processor Series Low Power Integrated x86 Solutions

Electrical Specifications (Continued)6.5.2.3 Definition of System Conditions for Measuring "On" ParametersProcessor current is highly dependent two functional characteristics,DCLK (DOT clock) and SDRAM frequency. processor current parameters.measuring the typical average and absolute maximumTable 6-6 shows how these factors are controlled whenTable 6-6. System Conditions Used to Determine CPU’s Current Used During the "On" StateCPU CurrentMeasurementSystem ConditionsV CC2 V CC3 FreqDCLKSDRAMFreqTypical Average Nominal Nominal 50 MHz NominalNote 2Absolute Maximum Max Max 135 MHz MaxNote 5Notes: 1.CommentsNotes 1 and 4Notes3,4,5,7A DCLK frequency of 50 MHz is derived by setting the display mode to 800x600x8 bpp at 75 Hz, using adisplay image of vertical stripes (4-pixel wide) alternating between black and white with power managementdisabled.2. SDRAM nominal frequency represents a single value that the memory controller can be configured for,between 66 MHz and 78 MHz, based on a given core clock frequency:166 MHz (5x) / 2.5 = 66.67 MHz180 MHz (6x) / 2.5 = 72.0 MHz200 MHz (6x) / 3.0 = 66.67 MHz233 MHz (7x) / 3.0 = 77.78 MHz266 MHz (8x) / 3.5 = 76.19 MHz3. A DCLK frequency of 135 MHz is derived by setting the display mode to 1280x1024x8 bpp at 75 Hz, usinga display image of vertical stripes (1-pixel wide) alternating between black and white with power managementdisabled.4. See Table 6-4 on page 189 for nominal and maximum voltages.5. SDRAM max frequency represents the highest frequency that the memory controller can be configured,up to 100 MHz, based on a given core clock frequency:166 MHz (5x) / 2.0 = 83.3 MHz180 MHz (6x) / 2.0 = 90.0 MHz200 MHz (6x) / 2.0 = 100.0 MHz233 MHz (7x) / 2.5 = 93.3 MHz266 MHz (8x) / 3.0 = 88.9 MHz6. SDRAM speeds between 79 MHz and 100 MHz are only supported for particular types of closed systemdesigns. Therefore, absolute maximum current will not be realized in most system designs. Refer to thede-rating curve in Figure 6-3 on page 195 to calculate absolute maximum current based on the system’sparameters.7. Not all system designs will support display modes that require a DCLK of 135 MHz. Therefore, absolutemaximum current will not be realized in all system designs. Refer to the de-rating curve in Figure 6-3 onpage 195 to calculate absolute maximum current based on the system’s parameters.Geode GXLV Processor SeriesRevision 1.3 191 www.national.com